Also important to note that a large number of Libertarians will vote third party. Libertarians love Trump. Not that he follows Libertarian ideology particularly well, but he provides a great validation of their theory of the total failure of all government in every situation. I'd expect most Libertarians to smugly vote for a 3rd party candidate with no hope of winning and be secretly quite happy when Trump is re-elected for this reason. Competent governance is (after all) the antithesis to Libertarian doctrine - so 'harm reduction' strategy is going to be roundly rejected by this crew. They really want the least competent government in power.
Libertarian-splaining :)
What you said actually makes some sense though.
There is a good argument to be made that the left leaning corporatist/centrist/globalist leadership class merely offers a thin veneer of competence. They are able to smoothly say the professional sounding words that make us nod and yawn while ultimately participating in a sort of managed decline rife with the endless little conflicts of interest layered throughout bureaucracies that ultimately end up leaving everyday people high and dry.
At least with Trump it's more plain to see that many things are moving in the wrong direction. Not because HE's moving us in the wrong direction (though he is) but because he has the opposite incentives that previous presidents have had to preserve order, decorum, and cohesion with our various counterparts.
For example, the current issue of the day. GW Bush and Obama, had they even arrived at the same conclusion, would have had to think long and hard before calling out the WHO for its complicity in validating Chinese propaganda regarding the status of Covid19. And their tone probably would have been much more conciliatory.
Meanwhile Trump is incentivized to do things like this. It's part of his campaign promise and part of his brand. He unfortunately overdoes it, fixating his sights on any random target that might offend or insult him in any minor way, which risks causing the "adults in the room" to have a knee jerk reaction to simply adopt the opposite position to whatever Trump's position is. And of course Trump doesn't do this when it's him or his own team that act unethically with conflicts of interest. But those are plain as day for us to see.
This is all to say the reason a libertarian would want to see another Trump term is NOT to see the incompetence of a Trump administration on full display (as the Trump presidency is a total aberration that would provide no validation of the incompetent government thesis), but to let the tactless loudmouth loose in the land of secrets to expose all of the conflicts of interest and incompetence he is uniquely incentivized to call out.
It might be ignored along with all of Trump's other nonsense, but astute and independent thinkers can differentiate.
https://www.theatlantic.com/ideas/archive/2020/04/consider-possibility-trump-right-china/609493/To play devil's advocate to myself, I don't see how any of these problems will get resolved with another 4 years of Trump. He is something of a broken clock identifying two problems a day and shoehorning in non-solutions that simply please his voter base. Trump's election was like tearing off your sheetrock and slapping tax cuts & not-so-quiet dog whistles on rotting studs. Electing Biden will be like simply putting the sheetrock back up.
So I occasionally vote 3rd party simply to try and grow the 3rd party number vs the previous vote so that voters will start considering 3rd parties to be more and more realistic and eventually offer us more options like other countries.